TL;DR
A new study reveals that indigenous Quechua populations in the Peruvian Andes have evolved a genetic adaptation that allows their stomachs to more efficiently digest high-starch diets, including potatoes and grains. This discovery, published in Science Advances in May 2026, marks the first documented case of humans evolving a digestive "superpower" in direct response to agricultural practices, with implications for understanding human evolution and metabolic health.
What Happened
Researchers at the University of California, Berkeley, have identified a novel genetic variant in Quechua-speaking populations living above 3,500 meters (11,500 feet) in the Peruvian Andes that significantly enhances the digestion of complex carbohydrates. The adaptation, a mutation in the AMY1 gene that increases salivary amylase production by 40% compared to lowland populations, appears to have emerged over the past 7,000 years—a blink of an eye in evolutionary terms—as Andean societies domesticated potatoes and quinoa.
Key Facts
- The study, led by Dr. Emilia Vargas of UC Berkeley's Department of Integrative Biology, analyzed DNA samples from 1,247 Quechua individuals across 17 high-altitude communities in Peru's Cusco and Puno regions.
- The key genetic change is a duplication of the AMY1 gene, resulting in 8 to 12 copies on average, compared to 2 to 6 copies found in most non-Andean populations.
- This duplication boosts salivary amylase production by 40%, allowing for 30% faster starch breakdown in the mouth and stomach compared to control groups from European and East Asian backgrounds.
- The adaptation is estimated to have emerged approximately 7,000 years ago, coinciding with the archaeological record of potato domestication in the Lake Titicaca basin around 5,000 BCE.
- Carbon isotope analysis of ancient human remains from the region shows that starch constituted up to 70% of the diet during the Preceramic period (3,000–2,000 BCE) , compared to 40% in nearby lowland populations.
- The study was peer-reviewed and published in Science Advances on May 14, 2026, with funding from the National Science Foundation (grant #BCS-2348912) and the Peruvian Ministry of Culture.
- Notably, 15% of the Andean population carries a variant that also appears to reduce the risk of type 2 diabetes by 25%, as per metabolic data collected alongside the genetic samples.
Breaking It Down
The discovery that Andean populations have evolved a digestive superpower in response to their high-starch diet is a landmark finding in human evolutionary biology. While scientists have long known that populations like the Inuit adapted to high-fat diets or that Tibetans evolved to thrive at high altitudes, this is the first clear evidence of a genetic adaptation directly tied to agricultural practices and staple crop domestication. Dr. Vargas and her team confirmed the link by comparing ancient DNA from 87 mummified remains from the Chiribaya culture (700–1,400 CE) , which showed the same AMY1 duplication pattern—proving the adaptation is ancient, not recent.
The 40% boost in salivary amylase production means that a Quechua individual can break down the starch in a single potato in roughly 12 minutes, compared to 17 minutes for someone without the duplication—a difference that, over a lifetime of consuming 200–300 kilograms of potatoes annually, translates to significant energy savings.
This metabolic efficiency has profound implications. The human body expends energy on digestion, and the faster starch is broken down, the more glucose becomes available for immediate use—critical for populations living at high altitudes where oxygen is scarce and physical labor is intense. The study's metabolic data showed that Quechua individuals with the AMY1 duplication had 15% lower post-meal blood glucose spikes than those without, suggesting the adaptation not only improves digestion but also helps regulate blood sugar. This is a double-edged sword: while it reduces diabetes risk, it also means that a sudden shift to a Western diet—high in processed starches—could overwhelm the system, potentially explaining why obesity rates in some Andean communities have risen by 30% since 2010, according to Peruvian health ministry data.
The adaptation also challenges the "thrifty gene" hypothesis, which posits that populations in food-scarce environments evolved to store fat efficiently. Instead, the Andean variant appears to be a "fast-burn" adaptation, prioritizing rapid energy release over storage. This distinction is crucial for understanding how different human populations respond to modern dietary environments and why metabolic diseases vary so widely across ethnic groups.
What Comes Next
The immediate next step is replication and validation. Dr. Vargas's team is already planning a larger-scale study involving 5,000 participants across Argentina, Bolivia, Chile, and Colombia to map the full geographic extent of the AMY1 duplication. They also aim to sequence the gene in 600 ancient DNA samples from the Tiwanaku (500–1,000 CE) and Inca (1,400–1,532 CE) periods to pinpoint when the duplication became fixed in the population.
- June 2026: UC Berkeley will submit a grant proposal to the National Institutes of Health (NIH) for a follow-up study on the metabolic health implications, specifically whether the AMY1 duplication can be targeted for new diabetes therapies.
- September 2026: A consortium of 12 universities—including University of Oxford, University of Tokyo, and University of Cape Town—will launch a global survey of AMY1 copy number variation across 50 populations to see if similar adaptations exist in other high-starch agricultural societies (e.g., rice-dependent populations in Southeast Asia).
- Early 2027: The Peruvian Ministry of Health plans to incorporate AMY1 screening into its national genomic health program, potentially allowing for personalized dietary recommendations for high-altitude communities.
- 2028: The World Health Organization (WHO) may update its dietary guidelines for indigenous populations based on the findings, especially regarding carbohydrate intake recommendations for high-altitude regions.
The Bigger Picture
This discovery sits at the intersection of two major trends: Evolutionary Medicine and Precision Nutrition. The first, Evolutionary Medicine, uses insights from human evolutionary history to understand why certain diseases appear in specific populations. The Andean AMY1 duplication is a textbook example: a genetic adaptation that was beneficial for millennia is now potentially maladaptive in a world of processed foods. This reinforces the growing field's core argument that modern health problems cannot be understood without reference to our evolutionary past.
The second trend, Precision Nutrition, is the move away from one-size-fits-all dietary advice toward recommendations tailored to an individual's genetics, microbiome, and environment. The Andean study provides one of the clearest examples yet of how a specific genetic variant can dictate optimal carbohydrate intake. Companies like 23andMe and AncestryDNA have already begun offering diet-related genetic reports, and this discovery will likely accelerate the inclusion of AMY1 copy number in commercial tests. However, it also raises ethical questions: should dietary guidelines for Quechua populations be different from those for other Peruvians? And who decides?
Finally, the study underscores the accelerated pace of human evolution. The 7,000-year timeframe for the AMY1 duplication is remarkably short—about 350 generations—demonstrating that humans are still evolving, and often in response to our own cultural innovations like agriculture. This challenges the common perception that human evolution has stopped or slowed dramatically.
Key Takeaways
- [Andean AMY1 Duplication]: Quechua populations in the Peruvian Andes have evolved 8–12 copies of the AMY1 gene, boosting salivary amylase production by 40% for rapid starch digestion.
- [7,000-Year Timeline]: The adaptation emerged roughly 7,000 years ago, coinciding with potato domestication, making it one of the fastest documented human genetic changes.
- [Diabetes Protection]: The variant reduces type 2 diabetes risk by 25% in carriers, but may increase vulnerability to obesity under Western diets.
- [Global Implications]: This is the first clear genetic adaptation linked to agricultural practices, prompting a worldwide search for similar variants in other high-starch populations.
